Previously posted methods don't work on Premium - here's what to do
One of the first things you'll notice with Vista are the new User Account Control dialogues. They can be exceedingly annoying, yet Microsoft has actually posted begging people NOT to turn it off.
However, if you are still using CRT's (and maybe this happens with some LCD screens), the dialogue is accompanied by a very jarring "re-synch" of the monitors. Every time that dialogue box comes up, my first monitor blinks, and my second monitor actually goes into a restart which takes 2 to 3 seconds. This is completely and utterly unacceptable.
Searching for a solution, I found a promising clue here: Link. However, when I attempted to follow those instructions, to run secpol.msc, I was greeted with an error that MMC Could not create the snap-in. Woops! After years in the XP Professional world, I have "stepped down" and am "only" running Vista Premium! Which means, apparently, no local security policy editor!
So, to make the UAC less annoying, without turning it off completely, requires a little more work on Premium Edition.
Here's what you do:
1: Press Start
2: type regedit
3: Click on the UAC prompt.
4: Edit->Find
5: Type in: PromptOnSecureDesktop
6: rightclick the entry, and select modify.
7: Change the value to 0
8: Close regedit, you are DONE!
No more icky flashing every time the dialogue comes up. Now, for the warning: this does weaken UAC slightly. Basically the secure desktop is supposed to prevent programs from doing wierd things to prevent you from being able to respond - such as "autoclicking" the prompt itself using various nefarious means. Myself, I would rather have some protection than none, because the jarring effect of the secure desktop at that prompt is so horrid, that without a way to turn it off, I'd just be turning off UAC completely.
This should work on all versions of Vista, unlike the secpol.msc method, which apparently will not work on Home Premium or Basic.